High Idle (2-3K) in Park/Neutral
I have a 97 D90 V8 and it has been running A-OK. I got back from a 2 hour trip and when I put the Auto transmission into Park, the idle jumped to 3K RPM. The same when I place it in Neutral. When I'm in Drive or Reverse or any low gear (3-2-1), it idles normally (800-1200). Any suggestions on what might be causing this? Thanks!